(1) Field of the Invention
The present invention relates to a microwave resonator suitable for a filter or an oscillator used in a microwave frequency range including and above the UHF band.
(2) Description of the Prior Art
Examples of known resonators employed in the above frequency range include a dielectric coaxial resonator and a ceramic resonator. The dielectric resonator comprises an equivalent circuit including one capacitance element and one inductance element connected in parallel. On the other hand, the ceramic resonator comprises an equivalent circuit including a series circuit having one inductance element and one capacitance element, and a further capacitance element connected parallel to the series circuit.
Since either resonator includes only one inductance element in the equivalent circuit, it is impossible to magnetically connect a plurality of resonators by utilizing the inductance element. Therefore, a filter formed of resonators connected in a multistep mode requires separate coupling members such as capacitors, and has the disadvantage of being bulky in construction.